Process for unhairing skins and hides



Patented Nov.

pair

No Drawing.

(GRANTED UNDER THE PROVISIONS OF El-IE ACT OF MARSH 3,

'WILLIAIVL EAU'TENSTBAUGl-I, 01 THIEB, GERMANY.

PROCESS UNHAIBING SKINS AND RIDES.

Application filed August 21, 1920.

T all w 710m it may concern:

Be it known STRAUCH, merchant, residing at Trier, many, have invented Improvements in Processes for that I, lViLLniu RAUTEN- Gercertain new and useful Unhairing Skins and Hides (for which I filed an appl-ication for patent in Germany on Ma 9,

1919), of which the following is a speci cation.

The tanning of animal hides being accompanied by the absorption of tanning matter,

ning process and exceeding the weight of the unhaired dry skin by the amount of absorbed tan would occur.

Nevertheless by the methods usually employed a corresponding increase of weight is never obtained and this can only be explained by a matter compensating more or weight of the tanning substance fixed by skin.

The loss of ing the preparation loss in dermal less. for the the dermal substance occurs durof hides and skins for the tanning process and particularly during the unhairing process.

by the sweating hides with a lime This is mostly done process or by treating the bath or sulphide of sodium.

The sweating of hides provokes a slackening of the roots of the bristles and hair by putrefaction which also attacks and albuminoids within the skin.

destroys the This results in a double loss in that the albuminous substances, as well a been fixed to them. are lost.

s the tan which would have Solutions of lime dissolve albumens and extract the socalled intercellular substance from the hides.

The dissolved substances very soon become putrid and also contaminate the hides themselves, so that the lime bath must be thrown away and renewed from time to time.

Sulphide of sodium destroys bristles and hair and damages the hides themselves.

Careful investigations have proved. that a depilatory bath extracts the albumens dissolved in the skin only up to a point where a certain balance between bumen in the bath and the solution of althat in the skin is attained. Therefore the depilatory bath should, if possible, be enriched with dermal substance and at the same time the latter must be prevents d from putrefying. If pos- Serial "No. 405,186.

1921, 41 STAT. L, 1313.)

sible such a depilatory should be chosen as will prevent putrefaction.

A. chemical fulfilling these requirements is barium hydroxide or strontium hydroxide. Where a lime bath which has not a sufiicient disinfecting power is used, a disinfectant suitable for that purpose, for example, creosote. should be added. It is not possible to say whether the use of such a lime bath has any later deleterious effect. A. barium hydroxide bath enriched with dermal substance has been tried and gives excellent results. i

Careful observations on practical work in tanyards made during several years proved the fact that. in a depilatory barium bath enriched up to a certain pointiwith dermal substance protected from becoming putrid. the hides do not lose any dermal substance.

It has even been observed recently that socalled empty hides absorbed albuminous substance from a bath containing a large amount of the latter, thus improving their quality.

The enrichment of the bath with dermal matter may be cheaply effected by the addition of parings of hides, decay of skins, ears, muzzles, etc, in the freshly prepared depilatory.

A barium hydroxide or strontium hydroxide depilatory after having been used for unhairing hides for a sufiicient time to be saturated with dermal matter may also be used. Up to the present time those experimenting with barium hydroxide as depilatory did not wait till the point just mentioned was attained. but emptied and renewed the bath as usual from time to time. This explains the unsatisfactory results obtained hitherto with barium hydroxide as a depilatory.

It has already been suggested 'to add albumen or albuminous matter tolime or caustic alkali as depilatory. but a lime depilatory containing albumen very soon becomes putrid and causticialkali very soon decomposes albumen, hence it is not possible by these methods to realize the purpose of enriching a depilatory for a certain period with albuminous substance.

The hairs bristles and paring of the hides after treatment according to my process are of the very best quality.

The process can be used for any sort of skin, hide or leather.

Special apparatus for cerrying out the process are not required;

Claim.

A process for unhairing skins or hides, which process consists in dissolving barium hydroxide in Water, adding to the solution hide substance until no more Will dissolve I thereimsOeking the skin or "hide to be treated 10 in the liquid and finally removing the heir 

